Sansa Connect: Retry AVR commands only 3 times

If the commands repeatedly fail it is likely that the AVR is not
programmed. In such case simply continue normal operation. This is
especially important in bootloader as it makes it possible to load new
rockbox build using bootloader USB mode. Otherwise, the only recovery
option would be to use I2C serial.

Change-Id: I4b0999833e9a906ec6353bdfdd5b68211f07ac81

1 files changed, 33 insertions, 16 deletions

diff --git a/firmware/target/arm/tms320dm320/sansa-connect/avr-sansaconnect.c b/firmware/target/arm/tms320dm320/sansa-connect/avr-sansaconnect.c
index 66cbb1931b..056ba7b56a 100644
--- a/firmware/target/arm/tms320dm320/sansa-connect/avr-sansaconnect.c
+++ b/firmware/target/arm/tms320dm320/sansa-connect/avr-sansaconnect.c
@@ -53,6 +53,7 @@
 #endif
 
 #define AVR_DELAY_US            100
+#define AVR_MAX_RETRIES         3
 
 #define CMD_SYNC                0xAA
 #define CMD_CLOSE               0xCC
@@ -428,26 +429,38 @@ static bool avr_run_command(uint8_t opcode, uint8_t *data, size_t data_length)
 }
 
 
-static void avr_hid_sync(void)
+static bool avr_hid_sync(void)
 {
     uint8_t data;
-    while (!avr_run_command(CMD_VER, &data, sizeof(data)))
+    int retry;
+    for (retry = 0; retry < AVR_MAX_RETRIES; retry++)
     {
-        /* TODO: Program HID if failing for long time.
-         * To do so, unfortunately, AVR firmware would have to be written
-         * from scratch as OF blob cannot be used due to licensing.
-         */
+        if (avr_run_command(CMD_VER, &data, sizeof(data)))
+        {
+            return true;
+        }
     }
-
+    /* TODO: Program HID as it appears to be not programmed.
+     * To do so, unfortunately, AVR firmware would have to be written
+     * from scratch as OF blob cannot be used due to licensing.
+     */
+    return false;
 }
 
-static void avr_execute_command(uint8_t opcode, uint8_t *data, size_t data_length)
+static bool avr_execute_command(uint8_t opcode, uint8_t *data, size_t data_length)
 {
-    while (!avr_run_command(opcode, data, data_length))
+    int retry;
+    for (retry = 0; retry < AVR_MAX_RETRIES; retry++)
     {
+        if (avr_run_command(opcode, data, data_length))
+        {
+            return true;
+        }
+
         /* Resync and try again */
         avr_hid_sync();
     }
+    return false;
 }
 
 void avr_hid_init(void)
@@ -499,18 +512,22 @@ bool charging_state(void)
 static void avr_hid_get_state(void)
 {
     uint8_t state[8];
-    avr_execute_command(CMD_STATE, state, sizeof(state));
-
-    avr_battery_status = state[6];
-    avr_battery_level = state[7];
-    parse_button_state(state);
+    if (avr_execute_command(CMD_STATE, state, sizeof(state)))
+    {
+        avr_battery_status = state[6];
+        avr_battery_level = state[7];
+        parse_button_state(state);
+    }
 }
 
 static uint32_t avr_hid_get_monotime(void)
 {
     uint8_t tmp[4];
-    avr_execute_command(CMD_MONOTIME, tmp, sizeof(tmp));
-    return (tmp[0]) | (tmp[1] << 8) | (tmp[2] << 16) | (tmp[3] << 24);
+    if (avr_execute_command(CMD_MONOTIME, tmp, sizeof(tmp)))
+    {
+        return (tmp[0]) | (tmp[1] << 8) | (tmp[2] << 16) | (tmp[3] << 24);
+    }
+    return 0;
 }
 
 static void avr_hid_enable_wheel(void)